SSLManager causes a crash

[pqvst]

If you create an instance of a HTTPSClientSession without providing a Context (which is possible with the available constructors), then the SSLManager will cause a crash during destruction.

// crash
int main()
{
    Poco::Net::HTTPSClientSession session;
}

Note however if you manually shutdown the SSLManager before termination then the crash doesn't occur.

// no crash
int main()
{
    Poco::Net::HTTPSClientSession session;
    Poco::Net::SSLManager::instance().shutdown();
}

[cryptoknight]

This seems to be a long running defect: http://pocoproject.org/forum/viewtopic.php?f=12&t=5087&p=8146&hilit=sslmanager

On my project, we have the shutdown call inside the destructor of all our Poco::Applications. Would be good to be able to remove it one of these days.

[aleks-f]

This is probably best solved in the same manner as Net initialization on Windows

If someone tests it and sends a pull request, I'll be happy to merge it.